Clinical and Refractive Outcomes of Toric Phakic Implantable Collamer Lens Implantation for correction of myopic astigmatism

Background: Currently there are four general approaches to correct refractive errors: refractive corneal surgery, crystalline lens surgery and implantation of an intraocular lens in anterior or posterior chamber. Aim: To evaluate the predictability, safety and stability of toric phakic implantable collamer lens implantation to correct moderate to high myopic astigmatism. Methods: Sixty eyes of 40 patients underwent implantation of a toric implantable collamer lens (V4c design) in the Eye Specialty Private Hospital, Baghdad, Iraq were studied. The mean spherical refraction was -11.32±3.17 diopter (D) with a range of -6.00 to -18.00 D and a mean cylinder of -2.61±1.16 with range of -1.00 to -5.50 D. The outcome measures that evaluated during a 12 months follow-up period include UDVA, refractive outcomes, CDVA, vault and adverse events. Results: At 12 months postoperatively, the mean Snellen decimal UDVA was 0.77±0.23 and the mean CDVA was 0.80±0.21, with an efficacy index of 1.16. Twenty nine eyes (48.33%) showed gain in CDVA with a safety index of 1.21. The treatment was highly predictable for spherical equivalent and astigmatic component. The mean SE dropped from -12.63±3.11 D to -0.11±0.20 D with 58 eyes within ±0.50 D and 60 eyes with ±1.00 D of the target correction. For achieved cylinder 60 eyes (100%) had ≤0.50 D and 51 eyes (85%) had ≤0.25 D with a strong positive linear correlation between achieved and expected cylinder (r=0.94). Conclusion: The results of the present study support safety, efficacy, predictability of toric implantable collamer lens implantation to treat moderate to high myopic astigmatism Abbreviation: UDVA: uncorrected distance visual acuity, CDVA: corrected distance visual acuity, SE: spherical equivalent and ACD: anterior chamber depth